Re: Mac Address Change

Jeff Liebermann <jeffl@xxxxxxxxxxxxxxxxxxxxxx> wrote in
news:gmm192tmtvkce5k34c141fboilsafa1qoc@xxxxxxx:

JDavidson <JDavidson@xxxxxxx> hath wroth:

So, the easiest way to change the MAC sent to the ISP gateway router
is to change the MAC of the computer and then clone the MAC at the
radio/ bridge (assuming there is no router, or at the router if you
use one)?

The MAC address sent to the ISP gateway can be manually entered in the
"clone MAC address" field on the router. For example, the WRT54G
setting is at:
http://www.linksysdata.com/ui/WRT54G/v5/1.00.6/WanMAC.htm
You can copy it from the PC with the "clone" button, or just type in
any mess of numbers you find entertaining. I strongly suggest you do
not duplicate the MAC address of the ISP gateway, or the connected
router, or nothing will work.

some question as to whether most of these AP's could be running security
programs to detect phoney MAC addresses, in which case make "any numbers
you find entertaining" not good advice.

You say most routers allow this, what about wireless ethernet bridges?

A few allow it to be changed. I just checked a random assortment.
The Linksys WAP11 and WAP54G do NOT. The WET54G does:
http://www.linksysdata.com/ui/WET54G/v2/advanced.shtml
(at bottom under "clone mode").

Don't know why you default to WAP11 or other linksys/dlink toys? Have
read they are not any good, according to user reports, or are too weak
generally speaking for remote access, unless supplemented with a good
antenna; probaby iffy even at that.


How to determine if the bridge (or router if used) allows for
cloning of the computers MAC prior to purchase?

Easy. There are emulators for most routers online:
Linksys:
http://www.linksysdata.com/ui/
Dlink:
http://support.dlink.com/faq/view.asp?prod_id=1457
There may be others but I'm too lazy to find them. For everything
else, I'm afraid you'll have to read the downloadable manuals.
Unfortunately, such "advanced" features are often not documented.

Notice you put "advanced" in quotes, they should all have this feature.


How about a clue as to what you're trying to accomplish?

My guess is that you're worried that your unspecified wireless client
radio can be locked out by blocking the MAC address. In the case of a
wireless card plugged directly into a computah, the MAC address can
easily be changed by one of the aformentioned utilities. For an
ethernet connected wireless bridge, game adapter, or client mode
mumble mumble bridge, the MAC address can be changed on some (not all)
such devices. Because of the ease of which this can be done, and the
not so minor detail that MAC addresses can be sniffed, filtering by
MAC address is totally worthless.


Just finished reading a few papers on security software that can detect
real MACs from made up/cloned MAC addresses and block access on that
basis. Used to block people who are engaged in attempts to break into a
network or run a rogue AP. Sounds like they can still block by MAC
address and other ways-RF fingerprint, etc. to disallow access based on
whatever criteria they want. Maybe they are not even trying to block at
all, maybe I just have had power/signal problems, but seems prudent to
determine if they have the capability to block capriciously if they so
decide before investing money in equipment they have the power to
effectively turn off. At least if I pay for cable/dsl, I can have a
reasonable expectation that they have to provide the service, not so
with some gov. admin'ed wireless link.
.

Relevant Pages

  • RE: bridge detection
    ... A router will use its own MAC address as the source. ... A bridge, therefore, is not an issue. ... But a router or proxy ...
    (Security-Basics)
  • Re: Question for Jeff Liebermann
    ... directly to the router, after it has been working behind the wireless ...  But it has no problem moving from bridge to router. ... the ethernet card MAC. ... not that of the wireless bridge. ...
    (alt.internet.wireless)
  • Re: Sending big files to a friend.
    ... which makes sense in terms of the controls that my router supplies. ... connect to my Mac in that fashion from the Internet via my ADSL ... A game or application is made up of one or more TCP/UDP port ranges. ... Because the internet IP that your prvider assigns to you is dynamic. ...
    (uk.comp.sys.mac)
  • Re: Question for Jeff Liebermann
    ... But it has no problem moving from bridge to router. ... the ethernet card MAC. ... Then after plugging the computer into the wireless bridge, ...
    (alt.internet.wireless)
  • Re: Question for Jeff Liebermann
    ... which sits behind a router. ... bridge seems to be working, as the computer attached to it can get on ... router in the ARP table. ... to dump the current MAC -> IP address values. ...
    (alt.internet.wireless)